A 41-year-old Israeli colonel was killed, and another officer was wounded in combat in northern Gaza on Sunday, the Israeli military said.
Israel's Channel 12 and public broadcaster Kan reported an explosive device had gone off under a tank.
Meanwhile, officials in Gaza said rescuers were still recovering people from the rubble after an Israeli attack that killed dozens.
At least 87 people were dead or missing following the air strike on Beit Lahiya in northern Gaza late on Saturday, the health ministry in the Palestinian territory said, one of the highest death tolls for months from a single attack. Israel said it was investigating reports of the incident.
It marked an intensification of Israel's offensives against Hamas in Gaza.